For those of us who don't understand SQL injection, please explain this.
Speed cameras take a picture of your license plate, use optical character recognition (OCR) to translate the image into text, and put your license plate into a database.
Instead of just a license plate, he's constructed a SQL command (Database control language) to wipe out the database.
So, if this works, if his car was tagged by a speed camera for speeding, instead of getting a ticket, the entire database the speed camera company was using would get wiped out.